diff --git a/src/output/OutputThread.cxx b/src/output/OutputThread.cxx
index 53fc2edfb..cfc68a877 100644
--- a/src/output/OutputThread.cxx
+++ b/src/output/OutputThread.cxx
@@ -132,8 +132,13 @@ AudioOutput::CloseFilter()
 		software_mixer_set_filter(*mixer, nullptr);
 
 	delete replay_gain_filter_instance;
+	replay_gain_filter_instance = nullptr;
+
 	delete other_replay_gain_filter_instance;
+	other_replay_gain_filter_instance = nullptr;
+
 	delete filter_instance;
+	filter_instance = nullptr;
 }
 
 inline void